Volatiles (nitrogen, noble gases) in recently discovered SNC meteorites, extinct radioactivities and evolution

Details Volatiles (nitrogen, noble gases) in recently discovered SNC meteorites, extinct radioactivities and evolution Volatiles (nitrogen, noble gases) in recently discovered SNC meteorites, extinct radioactivities and evolution

Sep 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003e%26psl.214...27m&link_type=abstract

Earth and Planetary Science Letters, Volume 214, Issue 1-2, p. 27-42.

Other

12

Mars, Snc Meteorites, Volatiles, Atmosphere, Nitrogen, Noble Gases

Scientific paper

We report noble gas and nitrogen analyses of newly discovered SNC meteorites, one nakhlite (NWA817) and four shergottites (NWA480, NWA856, NWA1068, and SaU 005). The K-Ar age (1.3 Ga) as well as the cosmic-ray exposure (CRE) age (10.0+/-1.3 Ma) of nakhlite NWA817 agree with data of Nakhla. The CRE ages of NWA480, NWA856, and NWA1068 (2.35+/-0.20, 2.60+/-0.21 and 2.01+/-0.65 Ma, respectively) are consistent, within uncertainties, with other basaltic shergottites, but the CRE age of SaU 005 (1.25+/-0.07 Ma) is distinct and indicates a different ejection event. Bulk K-Ar ages of all shergottites exceed the reported radiometric ages and reveal the presence of inherited radiogenic 40Ar in basaltic lavas. The isotopic composition of nitrogen trapped in these SNC meteorites is not homogeneous, since δ15N values of either +15 to 20‰ or +45‰, indicate different nitrogen reservoirs. All shergottites contain fission xenon from 238U, and fission Xe of extinct (T1/2=82 Ma) 244Pu, previously identified in ALH84001, in Chassigny and in Nakhla is also present in at least one shergottite (NWA856). The shergottites contain less fissiogenic Xe than other SNC, suggesting that either their source was more degassed or that the magma source region closed at a later time. In nakhlites, fission xenon from 244Pu correlates with uranium, a geochemical proxy of plutonium. Thus it is possible that fissiogenic Xe was not inherited during magma differentiation, but rather was produced in situ and retained in refractory mineral assemblages. In this interpretation, the magma evolution that settled the mineralogy and geochemistry of nakhlites took place at a time when 244Pu was alive and pre-dated the (late) events recorded in their radiometric ages. Alternatively, fissiogenic xenon was trapped from a mantle source during closed system evolution of the parent magmas, in which case such evolution might have taken place at considerable depth (pressure) in order to inhibit magma degassing during the course of differentiation.

Affiliated with

Also associated with

No associations

Rating

Volatiles (nitrogen, noble gases) in recently discovered SNC meteorites, extinct radioactivities and evolution does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Volatiles (nitrogen, noble gases) in recently discovered SNC meteorites, extinct radioactivities and evolution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Volatiles (nitrogen, noble gases) in recently discovered SNC meteorites, extinct radioactivities and evolution will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1152456